Abnormalities of Zinc and Copper During Total Parenteral Nutrition

Abstract

Changes in serum Zn and Cu levels were studied in 19 tumor bearing patients undergoing parenteral nutrition (TPN) for 5-42 days. Before initiation of i.v. feeding mean serum Zn and Cu concentrations were within normal limits but during TPN levels decreased significantly below those measured prior to parenteral nutrition. During TPN N, Zn, and Cu intake, urinary output and serum levels were studied prospectively in 9 patients. These 9 patients exhibited positive N retention based on urinary N excretion, but elevated urinary Zn and Cu excretion and lowered serum Zn and Cu concentrations. Neither blood administration nor limited oral intake was consistently able to maintain normal serum levels of Zn or Cu. Zn and Cu supplementation of hyperalimentation fluids in 4 patients studied for 5-16 days was successful in increasing serum Zn and Cu levels in only 2. Patients undergoing parenteral nutrition may require supplementation of Zn and Cu to prevent deficiencies of these elements.